With a communication service provided by a communication common carrier as of today, sequence in which packets sent out to an identical address by a plurality of users who are geographically apart from each other enter a net of the communication common carrier is not necessarily equal to sequence in which the packets at the address outgoes from the net because transmission delay varies due to a difference in physical distance, and so forth, occurring between the user, and the address, or between the users.
Accordingly, in the case of a transaction in which a processed result is dependent on sequence of executions of processing, including an electronic commercial transaction via a network such as, for example, an internet auction, ticket purchasing, selling/buying of stock and currency, and so forth, even a slight time difference due to transfer delay occurring between users having conflicted interests will cause advantageous/disadvantageous relationships, so that it is not possible to maintain impartiality for service provided. In the case where a processing request is transferred via a network to be then processed, the processing request sent out to the network is transferred to a relevant server, to be accompanied by transfer-delay corresponding to a physical distance up to the server for executing processing, and so forth, before being subjected to acceptance processing. That is, sequence in which the processing request is subjected to the acceptance processing will be dependent on not only sequence in which the processing request is sent out but also transfer-delay time accompanying communication.
As a method for overcoming this problem, a method is available whereby a processing request from a user is provided with a time stamp, and the processing request is rearranged in a different sequence by a server for processing a transaction. In Japanese Unexamined Patent Publication No. Hei11(1999)-259386, a server has a function for causing time synchronization between terminals used by users, and providing a processing request from a user, sent out by the terminal, with a time stamp, and the server for processing a transaction rearranges sequence in which the processing requests are processed on the basis of the time stamp imparted to each of the processing requests instead of sequence in which the requests are received, thereby implementing execution of processing according to sequence in which the processing requests are sent out.
More specifically, the following contents are disclosed in Japanese Unexamined Patent Publication No. Hei11(1999)-259386. A client machine periodically receives an absolute time from a time server, thereby executing time correction of a timer of the client machine by use of the absolute time as received. Respective client machines send out a service data request for receiving delivery of various types of services, and time data (the absolute time) of the timer to a server machine via Internet. The controller of the server machine controls the service data requests to be sequentially stored in a memory so as to be sorted out in an increasing order of the absolute time on the basis of the time data (the absolute time) imparted to the respective service data requests. Further, the server machine is provided with a timer for counting time elapsed from a time when each of the service data requests of the respective client machines arrives at the controller. The maximum transfer time of transfer time between the server machine, and the respective client machines is taken as maximum delay time, and the server machine holds each of the service data requests for a period corresponding to the maximum delay time before execution of processing of the service data requests.